Electrochemically Fabricated Structures Having Dielectric or Active Bases and Methods of and Apparatus for Producing Such Structures

ABSTRACT

Multilayer structures are electrochemically fabricated on a temporary (e.g. conductive) substrate and are thereafter bonded to a permanent (e.g. dielectric, patterned, multi-material, or otherwise functional) substrate and removed from the temporary substrate. In some embodiments, the structures are formed from top layer to bottom layer, such that the bottom layer of the structure becomes adhered to the permanent substrate, while in other embodiments the structures are formed from bottom layer to top layer and then a double substrate swap occurs. The permanent substrate may be a solid that is bonded (e.g. by an adhesive) to the layered structure or it may start out as a flowable material that is solidified adjacent to or partially surrounding a portion of the structure with bonding occurring during solidification. The multilayer structure may be released from a sacrificial material prior to attaching the permanent substrate or it may be released after attachment.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/191,258 (Microfabrica Docket No. P-US104-B-MF), filed Aug. 13, 2008.The '258 application is a continuation of U.S. patent application Ser.No. 10/841,006 (P-US104-A-MF), filed May 7, 2004, now abandoned. The'006 application is a continuation-in-part of U.S. patent applicationSer. No. 10/434,493 (P-US065-A-MG), filed on May 7, 2003, now U.S. Pat.No. 7,250,101. The '493 application claims benefit of U.S. ProvisionalApplication Nos. 60/442,656, and 60/379,177 filed on Jan. 23, 2003, andMay 7, 2002 respectively. These applications are incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

Various embodiments of some aspects of the present invention relategenerally to the field of Electrochemical Fabrication and the associatedformation of three-dimensional structures (e.g. parts, objects,components, or devices) via a layer-by-layer build up of depositedmaterials and to the processing of such structures after layer formationis complete so that the structures are transferred from a buildsubstrate (i.e. temporary substrate) to a structural substrate.

BACKGROUND

A technique for forming three-dimensional structures (e.g. parts,components, devices, and the like) from a plurality of adhered layerswas invented by Adam L. Cohen and is known as ElectrochemicalFabrication. It is being commercially pursued by Microfabrica® Inc.(formerly MEMGen Corporation) of Van Nuys, Calif. under the name EFAB®.This technique was described in U.S. Pat. No. 6,027,630, issued on Feb.22, 2000. This electrochemical deposition technique allows the selectivedeposition of a material using a unique masking technique that involvesthe use of a mask that includes patterned conformable material on asupport structure that is independent of the substrate onto whichplating will occur. When desiring to perform an electrodeposition usingthe mask, the conformable portion of the mask is brought into contactwith a substrate while in the presence of a plating solution such thatthe contact of the conformable portion of the mask to the substrateinhibits deposition at selected locations. For convenience, these masksmight be generically called conformable contact masks; the maskingtechnique may be generically called a conformable contact mask platingprocess. More specifically, in the terminology of Microfabrica® Inc.(formerly MEMGen Corporation) of Van Nuys, Calif. such masks have cometo be known as INSTANT MASKS™ and the process known as INSTANT MASKINGor INSTANT MASK™ plating. Selective depositions using conformablecontact mask plating may be used to form single layers of material ormay be used to form multi-layer structures. The teachings of the '630patent are hereby incorporated herein by reference as if set forth infull herein. Since the filing of the patent application that led to theabove noted patent, various papers about conformable contact maskplating (i.e. INSTANT MASKING) and electrochemical fabrication have beenpublished:

-   (1) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Batch production of functional, fully-dense metal parts    with micro-scale features”, Proc. 9th Solid Freeform Fabrication,    The University of Texas at Austin, p 161, August 1998.-   (2) A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P.    Will, “EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect    Ratio True 3-D MEMS”, Proc. 12th IEEE Micro Electro Mechanical    Systems Workshop, IEEE, p 244, January 1999.-   (3) A. Cohen, “3-D Micromachining by Electrochemical Fabrication”,    Micromachine Devices, March 1999.-   (4) G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.    Will, “EFAB: Rapid Desktop Manufacturing of True 3-D    Microstructures”, Proc. 2nd International Conference on Integrated    MicroNanotechnology for Space Applications, The Aerospace Co., April    1999.-   (5) F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, 3rd International    Workshop on High Aspect Ratio MicroStructure Technology (HARMST'99),    June 1999.-   (6) A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.    Will, “EFAB: Low-Cost, Automated Electrochemical Batch Fabrication    of Arbitrary 3-D Microstructures”, Micromachining and    Microfabrication Process Technology, SPIE 1999 Symposium on    Micromachining and Microfabrication, September 1999.-   (7) F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, MEMS Symposium, ASME 1999    International Mechanical Engineering Congress and Exposition,    November, 1999.-   (8) A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19 of    The MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press, 2002.-   (9) “Microfabrication—Rapid Prototyping's Killer Application”, pages    1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June    1999.

The disclosures of these nine publications are hereby incorporatedherein by reference as if set forth in full herein.

The electrochemical deposition process may be carried out in a number ofdifferent ways as set forth in the above patent and publications. In oneform, this process involves the execution of three separate operationsduring the formation of each layer of the structure that is to beformed:

-   -   1. Selectively depositing at least one material by        electrodeposition upon one or more desired regions of a        substrate.    -   2. Then, blanket depositing at least one additional material by        electrodeposition so that the additional deposit covers both the        regions that were previously selectively deposited onto, and the        regions of the substrate that did not receive any previously        applied selective depositions.    -   3. Finally, planarizing the materials deposited during the first        and second operations to produce a smoothed surface of a first        layer of desired thickness having at least one region containing        the at least one material and at least one region containing at        least the one additional material.

After formation of the first layer, one or more additional layers may beformed adjacent to the immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed.

The preferred method of performing the selective electrodepositioninvolved in the first operation is by conformable contact mask plating.In this type of plating, one or more conformable contact (CC) masks arefirst formed. The CC masks include a support structure onto which apatterned conformable dielectric material is adhered or formed. Theconformable material for each mask is shaped in accordance with aparticular cross-section of material to be plated. At least one CC maskis needed for each unique cross-sectional pattern that is to be plated.

The support for a CC mask is typically a plate-like structure formed ofa metal that is to be selectively electroplated and from which materialto be plated will be dissolved. In this typical approach, the supportwill act as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for CC masks to share acommon support, i.e. the patterns of conformable dielectric material forplating multiple layers of material may be located in different areas ofa single support structure. When a single support structure containsmultiple plating patterns, the entire structure is referred to as the CCmask while the individual plating masks may be referred to as“submasks”. In the present application such a distinction will be madeonly when relevant to a specific point being made.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of thesubstrate (or onto a previously formed layer or onto a previouslydeposited portion of a layer) on which deposition is to occur. Thepressing together of the CC mask and substrate occur in such a way thatall openings, in the conformable portions of the CC mask contain platingsolution. The conformable material of the CC mask that contacts thesubstrate acts as a barrier to electrodeposition while the openings inthe CC mask that are filled with electroplating solution act as pathwaysfor transferring material from an anode (e.g. the CC mask support) tothe non-contacted portions of the substrate (which act as a cathodeduring the plating operation) when an appropriate potential and/orcurrent are supplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-1C.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. FIG. 1A also depicts a substrate 6 separatedfrom mask 8. One is as a supporting material for the patterned insulator10 to maintain its integrity and alignment since the pattern may betopologically complex (e.g., involving isolated “islands” of insulatormaterial). The other function is as an anode for the electroplatingoperation. CC mask plating selectively deposits material 22 onto asubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 1C. The CC mask plating process is distinct from a“through-mask” plating process in that in a through-mask plating processthe separation of the masking material from the substrate would occurdestructively. As with through-mask plating, CC mask plating depositsmaterial selectively and simultaneously over the entire layer. Theplated region may consist of one or more isolated plating regions wherethese isolated plating regions may belong to a single structure that isbeing formed or may belong to multiple structures that are being formedsimultaneously. In CC mask plating as individual masks are notintentionally destroyed in the removal process, they may be usable inmultiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1F. FIG. 1D shows an anode 12′ separated from a mask 8′ that includesa patterned conformable material 10′ and a support structure 20. FIG. 1Dalso depicts substrate 6 separated from the mask 8′. FIG. 1E illustratesthe mask 8′ being brought into contact with the substrate 6. FIG. 1Fillustrates the deposit 22′ that results from conducting a current fromthe anode 12′ to the substrate 6. FIG. 1G illustrates the deposit 22′ onsubstrate 6 after separation from mask 8′. In this example, anappropriate electrolyte is located between the substrate 6 and the anode12′ and a current of ions coming from one or both of the solution andthe anode are conducted through the opening in the mask to the substratewhere material is deposited. This type of mask may be referred to as ananodeless INSTANT MASK™ (AIM) or as an anodeless conformable contact(ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the fabrication of the substrate onwhich plating is to occur (e.g. separate from a three-dimensional (3D)structure that is being formed). CC masks may be formed in a variety ofways, for example, a photolithographic process may be used. All maskscan be generated simultaneously, prior to structure fabrication ratherthan during it. This separation makes possible a simple, low-cost,automated, self-contained, and internally-clean “desktop factory” thatcan be installed almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A, illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the cathode 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode/substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A to 3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich the feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply for driving the blanket depositionprocess.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

In addition to the above teachings, the '630 patent indicates thatelectroplating methods can be used in combination with insulatingmaterials. In particular it indicates that though the electroplatingembodiments described therein have been described with respect to theuse of two metals, a variety of materials, e.g., polymers, ceramics andsemiconductor materials, and any number of metals can be depositedeither by the electroplating methods described above, or in separateprocesses that occur throughout the electroplating method. It indicatesthat a thin plating base can be deposited, e.g., by sputtering, over adeposit that is insufficiently conductive (e.g., an insulating layer) soas to enable subsequent electroplating. It also indicates that multiplesupport materials (i.e. sacrificial materials) can be included in theelectroplated element allowing selective removal of the supportmaterials.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal layers”. This patent teaches the formation of metalstructure utilizing mask exposures. A first layer of a primary metal iselectroplated onto an exposed plating base to fill a void in aphotoresist, the photoresist is then removed and a secondary metal iselectroplated over the first layer and over the plating base. Theexposed surface of the secondary metal is then machined down to a heightwhich exposes the first metal to produce a flat uniform surfaceextending across the both the primary and secondary metals. Formation ofa second layer may then begin by applying a photoresist layer over thefirst layer and then repeating the process used to produce the firstlayer. The process is then repeated until the entire structure is formedand the secondary metal is removed by etching. The photoresist is formedover the plating base or previous layer by casting and the voids in thephotoresist are formed by exposure of the photoresist through apatterned mask via X-rays or UV radiation.

A need still exists in the field for enhancing the combinability ofconducting materials, dielectric materials, semi-conducting materials,other materials, processed materials, and/or configured materials withinthe EFAB process. Furthermore, a need exists in the field for combiningelectrochemically fabricated structures with dielectric bases orsubstrates, active bases or substrates (bases or substrates havingelements that interact with the structure or that serve a purpose otherthan merely as a mount for the structure), and/or bases or substratescontaining contoured structures. A need remains in the field forimproved adhesion between bases or substrates and electrochemicallyfabricated structures. A need remains in the field for extending therange of capabilities, for expanding the range of materials, andprocesses available for forming desired structures (including theirbases or substrates).

SUMMARY OF THE INVENTION

It is an object of various aspects of the present invention tosupplement electrochemical fabrication techniques to expand thecapabilities of electrochemical fabrication process to meet thestructural and functional requirements for varying applications and thusto expand the potential applications available to the technology.

Other objects and advantages of various aspects of the invention will beapparent to those of skill in the art upon review of the teachingsherein. The various aspects of the invention, set forth explicitlyherein or otherwise ascertained from the teachings herein, may addressany one of the above objects alone or in combination, or alternativelymay not address any of the objects set forth above but instead addresssome other object ascertained from the teachings herein. It is notintended that all of these objects be addressed by any single aspect ofthe invention even though that may be the case with regard to someaspects.

A first aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto a temporary substrate, wherein thetemporary substrate may include previously deposited material; (B)forming a plurality of layers such that successive layers are formedadjacent to and adhered to previously deposited layers, wherein saidforming includes repeating operation (A) a plurality of times; (C) afterformation of a plurality of layers, attaching a structural substrateincluding a dielectric material to at least a portion of a layer of thestructure and removing at least a portion of the temporary substratefrom the structure.

A second aspect of the invention provides an electrochemical fabricationapparatus for producing a three-dimensional structure from a pluralityof adhered layers, the apparatus including: (A) means for selectivelydepositing at least a portion of a layer onto a temporary substrate,wherein the temporary substrate may include previously depositedmaterial; and (B) means for forming a plurality of layers such thatsuccessive layers are formed adjacent to and adhered to previouslydeposited layers, wherein said forming includes repeating operation (A)a plurality of times; (C) means for attaching a structural substrateincluding a dielectric material to at least a portion of a layer of thestructure and removing at least a portion of the temporary substratefrom the structure; and (D) a computer programmed to control the meansfor contacting, the means for conducting, the means for separating, andthe means for attaching, such that the means for attaching is made tooperate after formation of a plurality of layers of the structure.

A third aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto a first temporary substrate, wherein thefirst temporary substrate may include previously deposited material; and(B) forming a plurality of layers such that successive layers are formedadjacent to and adhered to previously deposited layers; and (C) afterformation of a plurality of layers attaching a second temporarysubstrate, which includes a dielectric material, to at least a portionof a layer of the structure and removing at least a portion of the firsttemporary substrate from the structure and then attaching a structuralsubstrate to at least a portion of a layer of the structure that atleast partially overlaps a location where the first temporary substratewas attached.

A fourth aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto a sacrificial substrate, wherein thetemporary substrate may include previously deposited material; (B)forming a plurality of layers such that each successive layer is formedadjacent to and adhered to a previously deposited layer, wherein saidforming includes repeating operation (A) a plurality of times; (C) afterformation of a plurality of layers attaching a structural substrate,including a plurality of materials and/or a patterned structure, to atleast a portion of a layer of the structure and removing at least aportion of the temporary substrate from the structure.

A fifth aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto a first temporary substrate, wherein thefirst temporary substrate may include previously deposited material; and(B) forming a plurality of layers such that successive layers are formedadjacent to and adhered to previously deposited layers; and (C) afterformation of a plurality of layers attaching a second temporarysubstrate, which includes a plurality of materials and/or includes apatterned structure, to at least a portion of a layer of the structureand removing at least a portion of the first temporary substrate fromthe structure and then attaching a structural substrate to at least aportion of a layer of the structure that at least partially overlaps alocation where the first temporary substrate was attached.

A sixth aspect of the invention provides an electrochemical fabricationprocess for producing a multi-part three-dimensional structure whereinat least one part is produced from a plurality of adhered layers, theprocess including: (A) forming at least one part of the multi-partstructure, including: (1) selectively depositing at least a portion of alayer onto a substrate, wherein the substrate may include previouslydeposited material; (2) forming a plurality of layers such thatsuccessive layers are formed adjacent to and adhered to previouslydeposited layers, wherein said forming includes repeating operation (1)a plurality of times; (B) supplying at least one additional part of themulti-part structure; (C) attaching the at least one part to the atleast one additional part to form the multi-part structure.

Further aspects of the invention will be understood by those of skill inthe art upon reviewing the teachings herein. Other aspects of theinvention may involve combinations of the above noted aspects of theinvention and/or addition of various features of one or moreembodiments. Other aspects of the invention may involve apparatus thatis configured to implement one or more of the above method aspects ofthe invention. These other aspects of the invention may provide variouscombinations of the aspects presented above as well as provide otherconfigurations, structures, functional relationships, and processes thathave not been specifically set forth above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-1G schematically depict a sideviews of various stages of a CC mask plating process using a differenttype of CC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various examplesubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4I schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself.

FIG. 5 depicts a flow chart of the basic operations of a preferredembodiment of the invention.

FIGS. 6A-6C depict an example of a structure created according to apreferred embodiment of the invention where FIGS. 6A and 6B depict twodifferent perspective views of the structure while FIG. 6C depicts aside view of the structure of FIGS. 6A and 6B.

FIGS. 7A-7O illustrate the production of the structure of FIGS. 6A-6Cfrom a plurality of adhered layers according to a preferred embodimentof the invention.

FIG. 8A-8D illustrate a variation to the formation of the last layer ofthe structure of FIGS. 6A-6C and how the permanent substrate mates withthat layer.

FIGS. 9A-9E depict the results of various steps during the practice ofan embodiment of the invention.

FIG. 10 provides a flowchart illustrating the basic operations of theembodiment exemplified in FIGS. 9A-9E.

FIGS. 11A-11J depict the results of various operations performed duringthe practice of an embodiment of the invention.

FIG. 12 provides a flowchart illustrating basic operations of anotherembodiment of the invention.

FIGS. 13A-13C schematically depict a process for swapping a structure702 from a first substrate 704 to a second substrate 706.

FIGS. 13D and 13E schematically depict side views of structures andsubstrates having modified configurations for enhancing attachment.

FIGS. 14A-14C schematically depict a process for modifying aconfiguration of an attachment layer of a structure to include notchesas indicated in FIG. 13D.

FIG. 15A-15F schematically depict a process for modifying aconfiguration of an attachment layer of a structure to include reentrantfeatures for enhancing interlocking of the structure and the substrate.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication that are known. Other electrochemicalfabrication techniques are set forth in the '630 patent referencedabove, in the various previously incorporated publications, in variousother patents and patent applications incorporated herein by reference,still others may be derived from combinations of various approachesdescribed in these publications, patents, and applications, or areotherwise known or ascertainable by those of skill in the art from theteachings set forth herein. All of these techniques may be combined withthose of the various embodiments of various aspects of the inventionexplicitly set forth herein to yield enhanced embodiments. Still otherembodiments be may derived from combinations of the various embodimentsexplicitly set forth herein.

FIGS. 4A-4I illustrate various stages in the formation of a single layerof a multi-layer fabrication process where a second metal is depositedon a first metal as well as in openings in the first metal where itsdeposition forms part of the layer. In FIG. 4A, a side view of asubstrate 82 is shown, onto which patternable photoresist 84 is cast asshown in FIG. 4B. In FIG. 4C, a pattern of resist is shown that resultsfrom the curing, exposing, and developing of the resist. The patterningof the photoresist 84 results in openings or apertures 92(a)-92(c)extending from a surface 86 of the photoresist through the thickness ofthe photoresist to surface 88 of the substrate 82. In FIG. 4D, a metal94 (e.g. nickel) is shown as having been electroplated into the openings92(a)-92(c). In FIG. 4E, the photoresist has been removed (i.e.chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first metal 94. In FIG. 4F,a second metal 96 (e.g., silver) is shown as having been blanketelectroplated over the entire exposed portions of the substrate 82(which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure areshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 4I to yield a desired3-D structure 98 (e.g. component or device).

Though the embodiments discussed herein are primarily focused onconformable contact masks and masking operations, the variousembodiments, alternatives, and techniques disclosed herein may haveapplication to proximity masks and masking operations (i.e. operationsthat use masks that at least partially selectively shield a substrate bytheir proximity to the substrate even if contact is not made),non-conformable masks and masking operations (i.e. masks and operationsbased on masks whose contact surfaces are not significantlyconformable), and adhered masks and masking operations (masks andoperations that use masks that are adhered to a substrate onto whichselective deposition or etching is to occur as opposed to only beingcontacted to it).

FIG. 5 presents the basic operations of a preferred embodiment of theinvention in the form of a flowchart. The process starts with operation102 which calls for supplying a substrate onto which successive layersof deposited material will be added. This substrate is typically madefrom a conductive material onto which electrodeposition can occur butmay be a dielectric material onto which a seed layer of conductivematerial has been deposited.

The process continues with operation 104 which calls for the depositionof a layer onto the substrate or onto a previously formed layer that isalready on the substrate. The layer deposited, according to certainembodiments of the invention will contain two or more materials one ormore of which are patterned to have a desired configuration for thestructure being formed and the other one or more materials acting assacrificial material which will be removed from the structure afterlayer formation is completed. As preferred embodiments of the inventioncall for the separation of the structure from the substrate on which itwas formed (i.e. the temporary substrate), and as it may be desirablefor the substrate to be made from a structural material as opposed to asacrificial material, in certain embodiments, the first one or morelayers deposited on the substrate may be comprised solely of sacrificialmaterial.

Furthermore, in preferred embodiments of the present invention, as thesubstrate on which structure is formed is not the permanent substrate onwhich the structure will reside, it is preferred in some embodiments forthe first layers deposited (of the structure) to be the last layers ofthe structure relative to the permanent substrate and the last layersdeposited to be the first layers relative to the permanent substrate. Inother words, in some embodiments it is desirable for the structure'slayers to be deposited in reverse order.

The electrochemical fabrication process used may be similar to the oneillustrated in FIGS. 1A-1C and 2A-2F or it may be another process setforth in the '630 patent, a process set forth in one of the otherpreviously incorporated publications, a process described in one of thepatents or applications that is included in the table of incorporatedpatents and applications set forth hereafter, or the process may be acombination of various approaches described in these publications,patents, and applications, or the process may be otherwise known orascertainable by those of skill in the art. Of course portions of thestructures may be formed by other three-dimensional modeling orfabrication processes.

After deposition of a layer, the process proceeds to operation 106 inwhich an inquiry is made as to whether the last layer of the structurehas been formed (i.e. the layer that will contact the permanentsubstrate in certain embodiments of the invention). If the answer is“no”, the process loops back to operation 104 for further depositions.If the answer is “yes”, the process moves forward to operation 108.

Operation 108 calls for the attachment of a permanent substrate (e.g. adielectric material) to the last deposited layer of the structure. Theattachment may occur via an adhesive (e.g. a pressure sensitiveadhesive, a heat sensitive adhesive, or a radiation curable adhesive (ifthe substrate is transmissive of the appropriate radiation). Theapplication of the adhesive may occur in various ways known to those ofskill in the art (e.g. spreading, spinning, spraying, and the like).Attachment may alternatively occur via non-adhesive based bondingtechniques, e.g. surface melting, sintering, brazing, ultrasonicwelding, vibration welding, and the like.

After attaching the permanent substrate and the layers of depositedmaterial together, the process proceeds to operation 110 where apermanent substrate and layers are separated from the temporarysubstrate and any sacrificial material is removed. The separationprocess may occur as a natural part of the sacrificial material removalprocess if one or more layers of sacrificial material are interposedbetween the temporary substrate and the structural material or if thetemporary substrate is made of the sacrificial material or othermaterial that is attacked by an etchant being used to selectivelyseparate the sacrificial and structural materials.

In alternative embodiments, the three tasks set forth in operations 108and 110 may be performed in varying orders, for example: (1) bonding andthen simultaneous separation and removal of sacrificial material, (2)bonding, separation, then removal, (3) simultaneous separation andremoval then bonding, (4) removal, bonding, then separation.

FIGS. 6A-6C depict an example of a structure (e.g. a switch) createdaccording to a preferred embodiment of the invention. Two differentperspective views of the structure are shown in FIGS. 6A and 6B and aside view is shown in FIG. 6C. The view seen in FIG. 6A allows thestructure 122 to be seen in its entirety while the structure is attachedto permanent substrate 124. The view seen in FIG. 6B obscures a portionof structure 122 when it is attached to permanent substrate 124 butallows the layer formation process to be seen when the structure isbeing formed and attached to the temporary substrate as shown in FIGS.7A to 7N. As can be seen in FIG. 6C the structure consists of ten layersnumbered 201-210.

FIGS. 7A-7O illustrate various states of the process associated with theformation of the structure of FIGS. 6A-6C. In this embodiment,successive layers are formed and adhered to the bottom of previouslydeposited layers. With the exception of the sacrificial material shownin FIG. 7B, when showing structural material and sacrificial material onthe current deposition layer, the structural material is fullyillustrated while only an outline of the sacrificial material is shown.On a current deposition layer any order of depositing structuralmaterial and sacrificial material is acceptable. In alternativeembodiments, the layers may be deposited one on top of the other or onebeside the other. In this application, unless a different interpretationis required by the context, when a deposition is said to occur onto aprevious deposition, no absolute inference of layer orientation shouldbe made but only a relative orientation of deposition order should beinferred.

FIG. 7A illustrates that the process starts with a temporary substrate212.

FIG. 7B indicates that the temporary substrate is supplied with acoating or first deposited layer 211 of sacrificial material. This layer211 of sacrificial material will allow separation of the structuralmaterial from the temporary substrate during a later step of theformation process. Of course in actual practice, more than one suchlayer 211 may be formed or its thickness may be tailored to allow easyseparation during a later step.

FIG. 7C shows the structural material 210′ of layer 210 that ispatterned along with a dashed outline indicating the boundary of thesacrificial material that is also present.

FIGS. 7D-7L increment through successive deposition layers ranging fromlayer 209 down to 201. The pattern of structural material 209′ to 201′for each of the current deposition layers is also shown along with anoutline of the sacrificial material associated with the current layer.Previously deposited layers are shown as solid blocks of materialwithout distinction between the patterning of the structural andsacrificial materials.

FIGS. 7M and 7N depict the attachment of the permanent substrate 200 to(1) the stack of layers 201-210, (2) the release layer 211, and (3) thetemporary substrate 212. FIG. 7M depicts the various elements of thepartially formed structures as solid blocks, while FIG. 7N depicts thesacrificial material and permanent substrate as transparent so that thelayers and configuration of the structural material 201′-210′ may beseen.

FIG. 7O depicts the released structural material 201′-210′ adhered tothe permanent substrate 200. The substrate is shown as transparent forillustrative purposes but which may be opaque or transparent (e.g.glass) wherein some applications may require or benefit from such amaterial (e.g. when the structure includes a scanning mirror that is toreceive radiation through the substrate and transmit it back out throughthe substrate). The temporary substrate may be removed along with thesacrificial material which may be removed by selective etching with anetchant (e.g. Enstrip C-38) that is selective to the sacrificialmaterial (e.g. copper) but non-destructive to the structural material(e.g. nickel). The sacrificial material etchant may include ananti-pitting agent, or the like, to help ensure that it does not attackthe structural material.

FIGS. 8A-8D illustrate a variation to the formation of the last layer ofthe structure of FIGS. 6A-6C and a variation in how the permanentsubstrate mates with that layer. FIG. 8A shows the final layer includingonly the structural material 201′. FIG. 8B depicts the permanentsubstrate being formed or adhered to not only the bottom of the lastlayer but also to the sides of the last layer such that the structuralmaterial of the last layer becomes at least partially embedded in thesubstrate. FIGS. 8C and 8D depict two perspective views of the resultingstructure. As can be seen, structural material 201′ is embedded in thesubstrate and only nine of the ten original layers of structuralmaterial extend above the surface of the permanent substrate. Thesurrounding of the structural material 201′ by the substrate may beachieved in various ways. For example, instead of the substrate being inthe form of a performed sheet that is bonded to the layers, it may be inthe form of a flowable material that can be molded to partially embedthe structural material and to have a desired thickness extending beyondthe surface of the last layer of structural material. As anotherexample, the substrate may still be in the form of a sheet that isbonded to the structural material 201′ of the last layer but a portionof the last layer where the sacrificial material has been removed ornever deposited may be filled with an epoxy or otherflowable/solidifiable material. The permanent substrate may be placed inposition and the hardening of the epoxy or other material may not onlyfill the region around structural material 201′ but also cause bondingbetween the layers and the substrate.

Various alternatives to the above embodiments exist. Even when notmolding the substrate around, the sides of at least one layer, it isstill possible to use a moldable material and form the substrate from atemporarily flowable material as opposed to a sheet of material. Contactpads and runners may be formed of the structural material and these mayextend to desired locations on the surface of the substrate or may evenbe encapsulated by the substrate material except at desired contactpoints. A selective partial etching of the sacrificial material mayoccur before attachment or formation of the permanent substrate. Layersof material may be etched to a depth of less than one layer thickness ormore than one layer thickness. In some embodiments, the depth of etchingmay be such that portions of the structural material may extendcompletely through the substrate that will be molded so as to forminterconnects that protrude from the bottom of the substrate. Inembodiments where it is desired to have interconnects extend through thebottom of the substrate, and when such extension does not occur duringmolding, the back side of the substrate may be planarized until thestructural material is exposed. Substrates need not be planar and theirlateral extents need not correspond to those of the layers.

If partially etching to a depth of more that one layer thickness, it ispreferred that the pattern of structural material remain of fixedpattern, for all but maybe the deepest layer that will be exposed by thepartial etching. This will help ensure a more uniform depth of etchingsince the sacrificial material will not be shielded by regions ofextended structural material. However, in embodiments where the depth ofetching is less critical or it is determined that a varying structuralpattern will yield a desired etching pattern, no such restriction onstructural material patterning need exist.

In some embodiments instead of the temporary substrate and permanentsubstrate being mounted on opposite sides of the deposited layers, thepermanent substrate may be mounted in an orientation perpendicular tothat of the temporary substrate. In other words, the permanent substratemay be mounted to the sides of a plurality of deposited layers.

In some embodiments, instead of attaching the permanent substrate to theopposite side of the stack of layers relative to the temporarysubstrate, the temporary substrate may be removed and the permanentsubstrate bonded in its place. This may occur by having the temporarysubstrate or its upper most surface formed of a material that can beselectively etched or otherwise removed from the layers of materialpreferably without damaging either the structural material orsacrificial material of those layers. And after removal, the bottom mostlayer of the structure would be exposed and the permanent substrate(e.g. dielectric substrate) attached thereto.

When desiring to mount the permanent substrate into the same positionoccupied by the temporary substrate, in some embodiments it may bedesirable to first mount a second temporary substrate on the oppositeside of the stack as compared to the first temporary substrate afterwhich the first temporary substrate may be removed, followed byattachment of the permanent substrate, and then followed by the removalof the second temporary substrate. In still other embodiments, thepermanent substrate can be mounted on the opposite side of the stack oflayers as compared to the substrate on which the layers were formed andthe substrate on which the layers were formed can remain.

In some embodiments of the invention, the permanent substrate may not bea dielectric but instead may be of some other material. For example, thepermanent substrate might be made of a conductive material that can notbe readily electrodeposited.

Though the use of the term “permanent substrate” has been used herein,it should be understood that it is not intended that the permanentsubstrate must exist throughout the life of the structure but insteadthat if form part of the structure for at least some portion of itsuseful life.

In some embodiments of the invention, a sacrificial material may not beused when depositing the layers one upon the other. In some embodiments,formation of layers may be by single or multiple selective depositionsand potentially one or more blanket depositions and potentially one ormore planarization operations.

Some embodiments of the invention may provide for attachment ofelectrochemically produced structures (e.g. structures formed usingconformable contact masking techniques or adhered masking techniques) tosubstrates that may include active elements. This is illustrated in theembodiment of FIGS. 9A-9E where an electrochemically fabricatedstructure is attached to a piezoelectric element and the combination ofthe two provide a working piezoelectric device.

In FIG. 9A, a structure 302 includes structural material 304 surroundedby a sacrificial material 306. The structure 302 is preferablyfabricated via electrochemical fabrication from a plurality of adheredlayers. The structure 302 is fabricated on a release material 308 whichin turn is attached to a substrate 312. The release material 308 may bethe same as the sacrificial material 306 or alternatively it may beanother material that can be separated, e.g. by etching or melting(e.g., a solder) or otherwise removed. The release material 308 may havebeen coated onto a substrate 312 prior to the start of electrochemicalfabrication of the structure 302 or it may be formed as a result of oneor more initial depositions of the electrochemical fabrication process.The substrate is typically a conductive material though in someembodiments it may be dielectric material which may be coated with aseed layer of conductive material.

In FIG. 9B, a pre-fabricated element or component 322 is shown locatedabove the structure 302. The pre-fabricated element or component 322 hasbeen prepared for attachment to the electrochemically fabricatedstructure 302. The element or component 322 is attached to a devicesubstrate 324. Typically, the device substrate 324 will serve as thefinal substrate for the device which will be a combination of element orcomponent 322 and the structural material of structure 302. Dependingthe final requirement of a particular device the device substrate maytake on any desired properties (e.g. be a conductor, a dielectric, atransparent material, a flexible material, etc.). In the present examplethe device substrate 324 is a dielectric so that it may provideelectrical isolation). On the device substrate a metal element 326 ispatterned, on to which a region of piezoelectric material 328 ispatterned, and on to which an adhesive 330 (which may be electricallyconductive if desired) is patterned. An appropriate adhesive is onewhich provides good adhesion to the structural material 304 of thestructure 302. The metal element 326 is provided and patterned to serveas an electrode to actuate the piezoelectric material and as a tracethat interconnects the electrode to a power supply.

In FIG. 9C, the pre-fabricated element or component 322 is shown asbeing adhered to structure 302 by means of the adhesive 330. In FIG. 9D,the release material 308 is shown as being removed. Finally, in FIG. 9E,the sacrificial material 306 has been removed from structural material304 to release component 334 from structure 302 thereby yielding thecompleted device 336 which is a combination of component 334, component322, and device substrate 324.

FIG. 10 provides a flow chart illustrating the process flow associatedwith the embodiment of FIGS. 9A-9E. In FIG. 10, the process begins attwo points as illustrated by blocks 402 and 406. Block 402 calls for thesupplying of a substrate that is separable from a component that will beformed thereon. The substrate and component might be separable as aresult of the substrate having a release layer thereon, or they might beseparable as a result of a release layer that will be formed on thesubstrate.

Block 406 calls for the supplying of a second component, where thesecond component will have a desired shape or will be composed ofmultiple desired materials. The second component will have a surfacethat can be attached to the surface of the first component as suppliedin association with block 402.

Block 404 calls for the formation of one or more layers on the substrateso as to form a first component (i.e. portion) of a device that is to becreated. In the process of forming the first component, the componentmay be partially surrounded by a sacrificial material which will beeventually removed from the component portion of the layers that areformed. The first component will have a surface that is capable of beingbonded or otherwise attached to the second component. Both blocks 404and 406 are the starting points for the operation of block 208.

In block 408 either one or both of the first and second components areprepared for adhesion to the other component by the addition of anadhesive to at least one of the bonding surfaces. Of course inalternative embodiments block 408 may not be part of the process. Insome embodiments, for example, an adhesive may be part of the secondcomponent that is supplied.

From block 408 the process moves forward to block 410 where the twocomponents are bonded or otherwise attached to one another. Thisattachment may occur by use of a pressure sensitive adhesive, a hot meltadhesive, or by other means known to those of skill in the art.

The process then moves forward to block 412 where the first component isseparated from the substrate on which it was formed.

Then the process moves forward to block 414 where the first component isseparated from any sacrificial material that is not to remain part ofthe final device that is being created.

Next the process moves to block 416 where either additionalmanufacturing operations may be performed or where the device that wasreleased in the operation of block 414 may be put to use.

In alternative embodiments, the order of operations associated withblocks 414 and 412 may be reversed. In still other embodiments theaccomplishment of the operations of blocks 414 and 412 may occursimultaneously. In still further alternative embodiments either one ofthe operations of blocks 412 or 414 or both of them may occur betweenthe operations of blocks 408 and 410. Various other alternatives will beapparent to those of skill of the art upon reviewing the teachingsherein.

In some embodiments of the invention the attached substrate may be apassive device but the structure that is attached to it may includestructures having electrochemically fabricated portions and portionsfabricated by other deposition or patterning techniques. One or both theportions may include active components. This is illustrated in theembodiment of FIGS. 11A-11J.

FIGS. 11A-11J illustrate another alternative embodiment of the inventionwhich includes formation of a number of layers using similar operationsfollowed by formation of additional portions of a structure usingalternative operations. FIG. 11A depicts a side view of a firststructure 502 which for illustrative purposes is identical to that ofFIG. 9A.

In FIG. 11B, a piezoelectric material 528 has been deposited onto thetop surface (i.e., last layer) of structure 502, and a photoresist 520has been deposited on to the piezoelectric material 528.

In FIG. 11C, a desired pattern of piezoelectric material 528 is shown.The patterning of this piezoelectric material may occur by firstpatterning the photoresist 520 which is then used as a pattern forselectively etching the piezoelectric material. In an alternativeprocess, for example, the piezoelectric material may have been patternedby lift-off methods, and the like.

FIG. 11D illustrates an optional step for bringing the surface level ofthe partially formed device to a uniform height by using a dielectricmaterial 532 to fill the voids that resulted from the etching of thepiezoelectric material. In some alternative embodiments, it may benecessary, or at least desirable, to planarize the combined dielectricand piezoelectric material layer.

FIG. 11E, depicts the resulting structure after deposition of a nextlayer that supplies a metal 534 on top of the piezoelectric anddielectric materials.

FIG. 11F, illustrates the result of an operation that patterns thedeposited metal. The pattern of the metal is selected to form anelectrode for the piezoelectric element as well as an interconnecttrace. The patterning of the metal may occur in a variety of ways, forexample, it may occur in one of the ways noted above for patterning thepiezoelectric material. FIG. 11G illustrates the result of an operationthat fills the voids in the metal layer with a dielectric material 536which may be the same as dielectric 532. The filling of the voids may becarried out in a manner similar to that used for filling the voids inthe piezoelectric containing layer. For example, a material may bedeposited in bulk, distributed, cured, and then planarized to yield alayer of desired thickness and uniformity. In FIG. 11H, a devicesubstrate 538 is illustrated as being applied over the metal/dielectriclayer. The substrate may have any desired properties and in the presentexample it is a dielectric. In FIG. 11I, a release material 508 is shownas having been removed. Finally, in FIG. 11J, a sacrificial material 508is shown as having been removed so as to yield a released device thatmay undergo additional processing operations or be put to use.

In a final functional device, an electric connection through thestructural material 304 of FIG. 9E or 504 of FIG. 11J may be used toprovide a second electrode for the piezoelectric element in order toproduce a functional device.

FIG. 12 provides a flow chart illustrating the process exemplified inFIGS. 11A-11J. The process starts with block 602 where a substrate issupplied onto which a device is to be formed. Also as the device will beeventually transferred to a different substrate the substrate shouldeither have a release layer already in place or alternatively anappropriate release material (e.g. sacrificial material) may be addedduring the first one or more layers of electrochemical fabrication.

Block 604 calls for the formation of one or more layers (e.g. byElectrochemical Fabrication) using a first process which will form aportion of the device which may be surrounded by a sacrificial material.

Block 606 calls for the use of at least one different deposition processto further build up and pattern the structure. In some embodimentsadditional electrochemical fabrication operations may be used incompleting formation of the structure which will include the unreleaseddevice.

Block 608 calls for the placement of an adhesive on the last layer ofthe formed structure and/or on a substrate that is going to be bonded tothe structure. The use of such adhesive may or may not be necessarydepending on the material that the substrate is made from and theprocess or processes that will be used to cause joining.

Block 610 calls for the formation of the substrate on the last formedlayer of the structure or the adherence on the substrate to the lastformed layer.

Block 612 calls for the separation of the structure from the originalsubstrate on which it was formed.

Block 614 calls for the separation of the structure from any sacrificialmaterial that is not to remain part of the final device. This separationwill result in a release of the device.

Block 616 calls for the performance of any additional fabricationoperations or the putting of the device into use. As with the flowchartof FIG. 10, various alternative operations may be performed as well asvarious reorderings of the blocks of the exemplified operations.

Two additional embodiments are depicted in FIGS. 13A-13E, 14A-14C, and15A-15F. These two additional embodiments depict substrate swappingtechniques that include either enhanced surface area (interlacing)between the structure and the adhered substrate or the formation offeatures in the structure that allow interlocking with the swappedsubstrate.

FIGS. 13A-13C schematically depict a process for swapping a structure702 from a first substrate 704 to a second substrate 706 where thecontact area between the structure and the second substrate issubstantially planar and thus no enhanced surface area or interlockingregions exist to aid in improving adhesion.

FIG. 13D depicts a modified structure 702′ and modified substrate 706′where notches exist in what was a planar surface of the structure andwhere protrusions in either the swapped substrate or in an adhesiveenter the notches and enhance adhesion between the structure andsubstrate.

FIG. 13E depicts a modified structure 702″ adhered to a modified swappedsubstrate 706″ where the structure includes notches with undercuts inwhich material from the swapped substrate or an adhesive becomes locatedsuch that adhesion between the structure and substrate is enhanced bymechanical interlocking between them.

The modified structure of FIG. 13D can be implemented via a number ofdifferent processes. One implementation is depicted in FIGS. 14A-14C.

FIG. 14A depicts the final two layers of the structure 712 and 714 asthey would have been produced when no interlocking would occur uponattachment of layer 714 to a substrate.

FIG. 14B depicts a modified version of layers 712 and 714′ where layer714′ is modified to include holes, notches, slots, or the like in thestructural material 718. These holes and notches may be filled with asacrificial material 720 as part of the layer formation process. FIG.14C depicts the state of the process after the sacrificial material 720shown in FIG. 14B is removed from the openings 722 in layer 714′.

In some embodiments, the openings in layer 714′ may have occurred duringthe layer formation process as a result of modifying the datadescriptive of the layer. Alternatively, in other embodiments the holesin layer 714′ may have been made after layer formation was completed byselectively etching holes into a layer 714 at desired locations. Suchetching processes may be performed using contact masks or adhered masks.The etching out of sacrificial material 720 on the other hand may occurin bulk if one is not concerned about removing sacrificial material fromother regions of the structure. Or alternatively, the etching may occurby use of one or more masks that at least shield regions of sacrificialmaterial that are not to be removed or that also shield the structuralmaterial. After the openings are etched into the layer which is tocontribute to adhesion, an adhesive or flowable substrate material maybe applied and the substrate bonded to the structure or solidified incontact with the structure (which results in bonding).

In some embodiments, it is preferable that the sacrificial materiallocated in regions outside the structural material portions of layer 714not be etched away prior to occurrence of the bonding operation. Suchordering of bonding and removal of sacrificial material may allow forimproved bonding orientation between the substrate and the structureand/or may help limit the movement of adhesive or flowable substratematerial into regions surrounding the structure. In other embodiments itmaybe preferable to remove the sacrificial material that is external tothe structural material regions, for example, as the sacrificialmaterial may be more accessible prior to bonding than after bonding.

In still other embodiments, external region etching may occur prior tobonding simply because the structures being bonded are relativelytolerant to non-uniformities in orientation or exact positioning and/orto the partial or complete filling of voids by flowable substratematerial or adhesive. The obtainment of data associated with modifyingthe last layer of the structure (or even the last several layers of astructure) may be based upon a designer modifying a CAD file descriptiveof the desired structure or by a data processing program that performsvarious Boolean operations (e.g. erosion or expansion operations) whichmay be based on fixed or user definable sets of parameters (e.g. a fixedgrid of attachment locations and sizes which can be overlaid against theexact position of the structural material of the layer or layers). Suchdata processing operations may be based on structural data that hasalready been transformed into layer data or it may be based onstructural data that remains in a three-dimensional format.

The gripping functionality of the transition region between thestructure and the substrate of FIG. 13E may be obtainable in a varietyof ways. For example, an etching operation may be used that has atendency to undercut the material that it is cutting into. Suchundercutting may be the result of the compression of a conformablecontact mask into the hole as it is being formed which may offerprotection for the upper portions of the side walls of the openingsuntil a certain depth is reached at which point horizontal etching mayform an undercut. Such gripping functionality may also be obtained bymodifying the pattern of structural material on the last two or morelayers of structure wherein the contacting layer (and maybe one or moreadditional layers will have relatively small openings in the structuralmaterial and one or more previous layers will have broader openings.These smaller openings and wider openings on different layers may befilled in with a sacrificial material during the layer formationprocess. The sacrificial material can be removed after layer formationis complete in much the same manner as described with regard to FIGS.14B and 14C. An example of the formation of these gripping, undercut, orinterlocking structures is depicted in FIGS. 15A-15F.

FIG. 15A depicts the last five layers of a sample structure formed byelectrochemical fabrication wherein each of the five layers has the sameconfiguration. As indicated, the structure includes regions ofstructural material 752 and regions of a sacrificial material 754 whichare external to the structure itself.

FIG. 15B depicts the last several layers of a structure formed byelectrochemical fabrication where the configuration of the last twolayers has been modified to include openings in the structural materialthat have undercuts or reentrant configurations. As shown in FIG. 15B,reentrant structures 762 and 764 as well as channels 772 and 774 thatlead to them are temporarily filled with a second sacrificial materialthat may or may not be the same as the first sacrificial material 754.

FIG. 15C depicts the pocket or reentrant structures 762 and 764 andassociated channels 772 and 774 with the second sacrificial materialremoved.

FIG. 15D depicts the structure after being coated with an adhesive 774and with a swapping substrate 776 located in position for bonding.

FIG. 15E depicts the state of the process after the swapping substrate776 has been lowered into position and bonded to the structure viaadhesive 774. Not only has bonding occurred between the substrate andthe structure, interlocking has occurred between the adhesive and thestructure, and if the adhesive has better bonding characteristics withthe substrate than the structure then the overall integrity of thecombined substrate-structure system has been improved.

FIG. 15F depicts the state of the process after the external sacrificialmaterial 754 has been removed.

Many alternatives to this interlocking approach as well as the increasedsurface area approach are possible. In either approach, the interlacingor interlocking elements may extend from a fraction of a layer tomultiple layers in height. Instead of using an adhesive to bond thesubstrate and the structure together, flowable substrate material mayhave been made to fill the openings after which it would be allowed tosolidify or otherwise be made to solidify.

In other embodiments the substrate itself could include openings orreentrant features which could assist in the gripping of an adhesive orfiller material to it. In still other embodiments the reentrant featuresmay not be such that any feature alone forms a locking pattern betweenthe substrate and the structure but where a combination of two or moresuch structures result in a locking configuration (e.g. straight holesextending into the structure at different angles).

In still other embodiments, the two elements to be attached may notinclude a multi-layer structure and a substrate, they may insteadinclude one or more multi-layer structures in combination with one ormore other elements or components that may or may not be multi-layerstructures, and may or may not be considered substrate-like.

One embodiment for forming interlock enhanced bonded structures may besummarized as follows: (1) obtain a file descriptive of the structure tobe formed; (2) modify the data so as to include one or more branches orchannels in the last one or more layers and pockets or reentrantstructures in one or more layers that immediately proceed the layersthat include the channels; (3) form the structure on a first substrate;(4) etch out the branches and pockets of the reentrant openings; (5)apply a flowable material to the surface of the structure that has thebranches or channels where the applied flowable material may be anadhesive if a separate substrate will be bonded by it or it may be asolidifiable material that will be cast or otherwise made to take theshape of a desired substrate; (6) bond the substrate and structure usingthe adhesive or solidify the substrate material so as to form asubstrate that is bonded to the structure; and (7) remove any othersacrificial material the remains and release the first substrate fromthe structure if desired and if not previously removed.

Many further alternative embodiments are possible and additionalexamples include: (1) the use of a single sacrificial material to fillthe openings as well as the regions external to the structure or to usemore then two sacrificial materials; (2) formation of the openings inthe structural material in such a way that a sacrificial material is notneeded to temporarily fill the openings; and/or (3) use of multiplestructural materials. The channels or branches leading to the pockets orreentrant features may have any desired length, they may vary incross-sectional dimension or they may have variable lengths. The pocketsor reentrant features need not have a size difference from that of thechannels as they may simply be offset from the position of the channelsand in this regard they may actually have smaller cross-sectional area;(5) there need not be a one to one correspondence between pockets andchannels; (6) the pockets themselves may have different heights, belocated at different depths within the structure and or have differentcross-sectional dimensions.

In other alternative embodiments, instead of using undercuts orreentrant features that penetrate into the interior of a structuralelement, it may be possible to form undercuts on the side walls ofregions of structural material which undercuts may be filled with abonding or substrate material and may act as interlocking elements whenconsidered in association with oppositely oriented undercuts on otherportions of the structural material.

In some embodiments, multi-layer structures may be formed starting witha “top” layer (i.e. intended last layer) which is formed adjacent to atemporary substrate, or possibly separated from the temporary substrateby one or more layers of sacrificial material and then adding onsubsequent layers until the first layer is reached. In these casessubstrate swapping may occur directly by attaching the structural (e.g.permanent substrate) to the last formed layer (e.g. intended firstlayer) and then, if not already done, the temporary substrate can beremoved. In some other embodiments, the multi layer structure can beformed starting with the intended first layer which may be formeddirectly on a temporary substrate or may be spaced from the temporarysubstrate by a sacrificial material which may or may not be the same asthe sacrificial material that forms part of the layers includingstructural material. The building may proceed from the first layer tothe last layer and if desired one or more layers of sacrificial materialmay be formed above the last layer. The sacrificial material above thelast layer may or may not be the same as the sacrificial material usedin forming the layers that contain both structural and sacrificialmaterials. If necessary, a second temporary substrate may be attached tothe last layer or the layers above it. The first temporary substrate(i.e. the initial substrate) may then be removed. If any layers ofsacrificial material exist below the first layer they may be removed andthereafter a permanent (or structural substrate) may be attached to thefirst layer, after which the second temporary substrate may be removedalong with any sacrificial material that has not yet been removed.

In some embodiments, the structural substrates may be rigid while inothers they may be flexible. In still other embodiments, the permanentsubstrates may be integrated circuits or other electrical components towhich attachment may be made by one or more of dielectric adhesives,wire bonds, re-flowed solder contacts, and/or other conductive ordielectric elements.

Many other alternative embodiments will be apparent to those of skill inthe art upon reviewing the teachings herein. Further embodiments may beformed from a combination of the various teachings explicitly set forthin the body of this application. Even further embodiments may be formedby combining the teachings set forth explicitly herein with teachingsset forth in the following patents and patent applications each of whichis hereby incorporated herein by reference:

US Pat App No, Filing Date US App Pub No, Pub Date Inventor, Title09/493,496 Cohen, Adam L, Method For Electrochemical Fabrication Jan.28, 2000 10/677,556 Cohen, et al., Monolithic Structures IncludingAlignment and/or Oct. 1, 2003 Retention Fixtures for AcceptingComponents Apr. 21, 2004 Cohen, et al., Methods of Reducing InterlayerDiscontinuities in Electrochemically Fabricated Three-DimensionalStructures 10/841,300 Lockard, et al., Methods for ElectrochemicallyFabricating May 7, 2004 Structures Using Adhered Masks, IncorporatingDielectric Sheets, and/or Seed layers That Are Partially Removed ViaPlanarization 10/271,574 Cohen, et al., Methods of and Apparatus forMaking High Aspect Oct. 15, 2002 Ratio Microelectromechanical Structures20030127336 A1 Jul. 10, 2003 10/697,597 Lockard, et al., EFAB Methodsand Apparatus Including Spray Dec. 20, 2002 Metal or Powder CoatingProcesses 10/677,498 Cohen, et al., Multi-cell Masks and Methods andApparatus for Oct. 1, 2003 Using Such Masks To Form Three-DimensionalStructures 10/724,513 Cohen, et al., Non-Conformable Masks and Methodsand Nov. 26, 2003 Apparatus for Forming Three-Dimensional Structures10/607,931 Brown, et al., Miniature RF and Microwave Components and Jun.27, 2003 Methods for Fabricating Such Components, 10/841,100 Cohen, etal., Electrochemical Fabrication Methods Including Use May 7, 2004 ofSurface Treatments to Reduce Overplating and/or Planarization DuringFormation of Multi-layer Three-Dimensional Structures 10/387,958 Cohen,et al., Electrochemical Fabrication Method and Application Mar. 13, 2003for Producing Three-Dimensional Structures Having Improved2003-022168-A1 Surface Finish Structures Having Improved Surface FinishDec. 4, 2003 10/434,494 Zhang, et al., Methods and Apparatus forMonitoring Deposition May 7, 2003 Quality During Conformable ContactMask Plating Operations 2004-0000489-A1 Jan. 1, 2004 10/434,289 GangZhang, Conformable Contact Masking Methods and May 7, 2003 ApparatusUtilizing In Situ Cathodic Activation of a Substrate 20040065555 Apr. 8,2004 10/434,294 Gang Zhang, Electrochemical Fabrication Methods With May7, 2003 Enhanced Post Deposition Processing Enhanced Post Deposition20040065550 Processing Apr. 8, 2004 10/434,295 Cohen, et al., Method ofand Apparatus for Forming Three- May 7, 2003 Dimensional StructuresIntegral With Semiconductor Based 2004-0004001 Circuitry Jan. 8, 200410/434,315 Christopher A. Bang, Methods of and Apparatus for Molding May7, 2003 Structures Using Sacrificial Metal Patterns 2003-0234179 Dec.25, 2003 10/434,103 Cohen, et al., Electrochemically FabricatedHermetically Sealed May 7, 2004 Microstructures and Methods of andApparatus for Producing 2004-0020782 Such Structures Feb. 5, 200410/841,347 Cohen, et al., Multi-step Release Method forElectrochemically May 7, 2004 Fabricated Structures 10/434,519 Dennis R.Smalley, Methods of and Apparatus for May 7, 2003 ElectrochemicallyFabricating Structures Via Interlaced Layers or 2004-0007470 ViaSelective Etching and Filling of Voids Jan. 15, 2004 60/533,947 Kumar,et al., Probe Arrays and Method for Making Dec. 31, 2003 10/724,515Cohen, et al., Method for Electrochemically Forming Structures Nov. 26,2003 Including Non-Parallel Mating of Contact Masks and Substrates

Various other embodiments of the present invention exist. Some of theseembodiments may be based on a combination of the teachings herein withvarious teachings incorporated herein by reference. Some embodiments maynot use any blanket deposition process and/or they may not use aplanarization process. Some embodiments may involve the selectivedeposition of a plurality of different materials on a single layer or ondifferent layers. Some embodiments may use blanket depositions processesthat are not electrodeposition processes. Some embodiments may usenickel as a structural material while other embodiments may usedifferent materials such as gold, silver, or any otherelectrodepositable materials that can be separated from the copperand/or some other sacrificial material. Some embodiments may use copperas the structural material with or without a sacrificial material. Someembodiments may remove a sacrificial material while other embodimentsmay not. In some embodiments, the depth of deposition may be enhanced bypulling the conformable contact mask away from the substrate asdeposition is occurring in a manner that allows the seal between theconformable portion of the CC mask and the substrate to shift from theface of the conformal material to the inside edges of the conformablematerial.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the instant invention will be apparent to those ofskill in the art. As such, it is not intended that the invention belimited to the particular illustrative embodiments, alternatives, anduses described above but instead that it be solely limited by the claimspresented hereafter.

1. A fabrication process for producing a three-dimensional structurefrom a plurality of adhered multi-material layers, the processcomprising: (A) forming a plurality of layers such that successivelayers are formed adjacent to and adhered to previously formed layersand wherein a first layer is formed adjacent to and adhered to atemporary substrate, wherein said forming of each of the plurality oflayers comprises: i) depositing at least one sacrificial material, ii)depositing at least one structural material, and iii) planarizing the atleast one sacrificial material and the at least one structural materialto set a boundary level of each layer; (B) after formation of at leasttwo layers of the plurality of layers, attaching a structural substratecomprising a dielectric material to at least a portion of at least onelayer of the structure and removing at least a portion of the temporarysubstrate from the structure; (C) before or after attaching thestructural substrate, or before or after removing the temporarysubstrate, removing sacrificial material from a plurality of layers torelease the three-dimensional structure which is formed from thestructural material.
 2. The process of claim 1 additionally comprising:(D) supplying a plurality of preformed masks, wherein each maskcomprises a patterned dielectric material that includes at least oneopening through which deposition can take place during the depositing ofthe at least one sacrificial material or the depositing of the at leastone structural material during forming of a given layer, wherein eachmask comprises a support structure that supports the patterneddielectric material, wherein at least a plurality of the depositingoperations comprise: i) contacting the temporary substrate and thedielectric material of a selected preformed mask; ii) in presence of aplating solution, conducting an electric current through the at leastone opening in the selected mask between an anode and a previouslyformed layer or the temporary substrate, wherein the anode comprises aselected deposition material, and wherein the previously formed layer ortemporary substrate functions as a cathode, such that the selecteddeposition material is deposited onto the previously formed layer ortemporary substrate to form at least a portion of a layer; and iii)separating the selected preformed mask from the temporary substrate. 3.The process of claim 1 wherein a plurality of selective depositingoperations comprise: (1) providing an adhered patterned mask on asurface of a previously formed layer or a surface of the temporarysubstrate, wherein the mask includes at least one opening; (2) inpresence of a plating solution, conducting an electric current throughthe at least one opening in the adhered mask between an anode and thepreviously formed layer or the substrate, wherein the anode comprises aselected deposition material, and wherein the previously formed layer orthe substrate functions as a cathode, such that the selected depositionmaterial is deposited onto the previously formed layer or the temporarysubstrate to form at least a portion of a given layer; and (3) removingthe mask from the previously formed layer or the temporary substrate. 4.The process of claim 1 wherein the attaching comprises placing adielectric adhesive onto at least one of the structural substrate or theat least portion of a bonding layer to which attachment is to occur andthen bringing the structural substrate and at least portion of thebonding layer into contact.
 5. The process of claim 1 wherein thestructural substrate is a preformed sheet that is bonded to the at leastportion of the bonding layer.
 6. The process of claim 1 wherein thestructural substrate comprises a flowable material that is contacted tothe at least portion of the bonding layer and is thereafter allowed tosolidify or is made to solidify.
 7. The process of claim 6 wherein theflowable material comprises a pre-polymer.
 8. The process of claim 7wherein the pre-polymer comprises a two-part epoxy.
 9. The process ofclaim 1 wherein the structural substrate comprises a flexible material.10. The process of claim 1 wherein the attaching operation causes thestructural substrate to at least partially surround at least a portionof the bonding layer of the three-dimensional structure.
 11. The processof claim 1 wherein the attaching of the structural substrate to thethree-dimensional structure comprises a mechanical interlocking ofportions of the structural substrate with portions of thethree-dimensional structure.
 12. The process of claim 11 wherein atleast one structural material is deposited after depositing at least onesacrificial material during the formation of a given layer.
 13. Theprocess of claim 11 wherein at least one sacrificial material isdeposited after depositing at least one structural material.
 14. Theprocess of claim 13 wherein at least a portion of the at least onesacrificial material is removed prior to attaching the structuralsubstrate.
 15. The process of claim 14 wherein the at least portion ofthe region from which sacrificial material that was removed is filledwith a dielectric material.
 16. The process of claim 15 wherein thestructural substrate comprises the dielectric material.
 17. The processof claim 13 wherein the structural substrate is attached to the at leastportion of the bonding layer prior to removal of the sacrificialmaterial.
 18. The process of claim 13 wherein upon release of thestructural material from the sacrificial material the structuralmaterial is also released from the temporary substrate.
 19. The processof claim 1 wherein the structural substrate comprises an electricalcomponent.
 20. The process of claim 1 wherein the structural substratecomprises an integrated circuit.
 21. The process of claim 1 wherein theattaching operation comprises one or more wire bonding operations thatattach one or more portions of the structure to one or more portions ofthe structural substrate.
 22. The process of claim 1 wherein theattaching operation comprises forming one or more reflowed soldercontacts between one or more portions of the structure and one or moreportions of the structural substrate.
 23. The process of claim 1 whereinthe temporary substrate comprises a first temporary substrate andwherein the structural substrate is attached after removing at least aportion of the first temporary substrate from the structure, and whereinthe process additionally comprises: (D) after formation of at least twolayers attaching a second temporary substrate, which comprises aplurality of materials and/or comprises a patterned structure, to atleast a portion of at least one layer of the structure and thereafterremoving at least a portion of the first temporary substrate from thestructure and then attaching the structural substrate to at least aportion of a layer of the structure that at least partially overlaps alocation where the first temporary substrate was attached.
 24. Afabrication process for producing a multi-part three-dimensionalstructure, wherein at least one part is formed from a plurality ofadhered multi-material layers, the process comprising: (B) Forming atleast one part of the multi-part structure, comprising: i) forming aplurality of layers such that successive layers are formed adjacent toand adhered to previously formed layers and wherein a first layer isformed adjacent to and adhered to a temporary substrate, wherein saidforming of each of the plurality of layers comprises: (1) depositing atleast one sacrificial material, (2) depositing at least one structuralmaterial, and (3) planarizing the at least one sacrificial material andthe at least one structural material to set a boundary level of eachlayer; ii) after formation of at least two layers of the plurality oflayers, attaching a structural substrate comprising a dielectricmaterial to at least a portion of at least one layer of the structureand removing at least a portion of the temporary substrate from thestructure; (C) supplying at least one additional part of the multi-partstructure; (D) attaching the at least one part to the at least oneadditional part to form the multi-part structure; (E) removing thetemporary substrate; (F) before or after attaching the at least one partto the at least one additional part, before or after removing thetemporary substrate, removing sacrificial material from a plurality oflayers to release the at least one part of the multi-layer part.